I'm not sure if it's the proper term, but I refer to the Rutherford reaction as Alpha bombardment of Nitrogen 14 to produce a Proton decay to Oxygen 17. Now, Nitrogen 14 is common as 70-80% of the air we breathe, so all you'd need is an Alpha source, like a Helion gun, or radioisotope, and liquid nitrogen tank to produce Oxygen, and Protons (Hydrogen nuclei) to react for energy.

Correct me if I'm wrong, but I was thinking that orbital gas miners could use this as fuel generation for LEO stations to power mass launches to orbit. Any forseeable problems with this?

_________________"You can't have everything, where would you put it?" -Steven Wright.

The main problem that I can see is that you'd need an incredible amount of radioactivity to create an appreciable amount of fuel in a reasonable time. I haven't done the math though.

_________________Say, can you feel the thunder in the air? Just like the moment ’fore it hits – then it’s everywhereWhat is this spell we’re under, do you care? The might to rise above it is now within your sphereMachinae Supremacy – Sid Icarus

Of all the charged particle reactions, D+T (deuterium + tritium)is the easiest to promote and requires the lowest collision energy of all known reactions. It has not been accomplished yet (except explosively), and when it is accomplished, that will be the basis for fusion power for some time, as the next easiest, D+D is much more difficult.

The reactions like B+H Li+H F+H N+He etc are very much more difficult--higher required collision energy and lower cross section (essentially probability of reacting from a collision).

There are many textbooks on nuclear reactions and I suggest reading a few.

Ben may be referring to the plasma discharge neutron generators, used in well logging and other applications calling for short pulses of neutrons. They work by accelerating a mix of D, T ions and hitting a carbon, titanium, or other hydride target. The voltage used for DT ones are about 50 KV and produce some millions of neutrons/discharge, The DD ones require about 150 KV and produce fewer neutrons.

The DD ones produce about 2.5 Mev, and DT about 14 Mev, and the neurtons carry off most of the energy (80% for DT). In a reactor, that energy is to be converted to heat in a lithium breeder blanket to make more T to be fed into the reactor.

The plasma tubes do not come anywhere near power out being as great as the power to run them. Confined plasma hot fusion may eventually be achieved. Most physics people think so.

"...and also inertial electrostatic confinement which is much more elegant. It is confined hot plasma DT fusion..."-----Electrostatic will probably not work, as that requires charged plasma, and electrostatic repulsion is so strong density of any such plasma will be way too low. Also it will be impossible to avoid short circuit of the high voltage gradients involved.=================

"Capturing neutron energy isn't as solved as you suggest..."------Capturing neutrons is easy. Every fission reactor does that and the engineering is well understood. Main difference between fission/fusion is that a high percentage of the total energy is from the neutrons. Probably just engineering issues, not a problem.=====================

"...and there are enough unknowns that a cold process may be possible..."------The famous Pons/Fleishman "process" was widsh driven hysteria. That never happened and cannot. Those who believe in it are using testimonials as arguments, not properly done, repeatable demonstrations. It has the hallmarks of religion.=================

"...just as a hot process may never break even."-------Hot confined plasma has not yet, but efforts are getting closer. Preponderance of opinion is that it can be done.

The ITER may do it. Then, from how that behaves, some improvement may lead to a practical reactor.

What about using a pair of particle accelerators and have the two streams collide? Stream D and stream T? I am not sure about this but I think temp.is harder to hold then momentum? You dont spend any energy on confinement.

_________________Let not the bindings of society hold you back from improving it.... the masses follow where the bold explore.

_________________Say, can you feel the thunder in the air? Just like the moment ’fore it hits – then it’s everywhereWhat is this spell we’re under, do you care? The might to rise above it is now within your sphereMachinae Supremacy – Sid Icarus

Sigma's idea:What about using a pair of particle accelerators and have the two streams collide? Stream D and stream T? I am not sure about this but I think temp.is harder to hold then momentum? You dont spend any energy on confinement.----------------

Problem with that is that only a small fraction of collisions result in reaction. Most just scatter an collisions between charged particles.

The total energy to make enough collisions per reacting one is greater than the output.

In a thermal confined plasma system the ions make many collisions before one reacts. The main energy loss here is "bremstrahlung" radiation--soft X rays from the high speed collisions of electrons with each other and ions. This energy comes out whether there are reactions or not.

So, a running thermal reactor will emit from the reacting volume X rays and neutrons of 2.5 and 14 Mev from DD and DT reactions respectively, and that will be absorbed in a blanket and converted to heat.

The blanket will have to be lithium, to use the neutrons to replace the tritium.

An additional problem is the need to minimise leakage of plasma from the confinement and evaporate wall material which would contaminate the plasma.

As the bremstrahlung effect is proportional to atomic number squared, 1% carbon in the plasma will increase X rays 36% ofer that from pure hydrogen.

10% helium in the plasma will increase that by 40% over that for pure hydrogen.

A likely wall material may be graphite, because, when hot the crystal structure tends to heal. Graphite fission reactors are periodically run to high temp to anneal and release the "Wigner energy", the energy stored up in the form of displaced atoms.

ckpooley, i meant "off the ground" case, about low acceleration -- Yep: there looks far better. as far as i know, Rosatom did step in to R&D compact reactor 4 low acceleration, SAFE-400 would be useful too. 4 propulsion, either VASIMIR or SPT-290.